createPrepareDownscaleEndpoints method expects a service name but sts.GetName() is passed. Hence, constructing an invalid FQDN to the pod to downscale with delay.

https://github.com/grafana/rollout-operator/blob/main/pkg/controller/delay.go#L64

Context:
For Grafana mimir ingesters, statefulsetse for each zones are created separately and use the headless service as the serviceName in the specs